i bc27f85be50b71b1 (161 page)

Table 8-7. Laboratory Tests for the Hepatic, Biliary. and Pancreatic Systems'"

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Test

Involved Systems

Purpose

Alanine aminotransferase (ALT, glutamic-

Hepatic

Used to detect hepatocellular injury.

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pyruvic transaminase ICPTI, SG�

Very specific in detecting acute hepatitis from

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transaminase)

viral, [Oxic, or drug-induced causes.

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Reference value: 10-35 IU/liter

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Alkaline phosphatase (ALP, total alkaline

Hepatic, biliary

Nonspecific indicator of liver disease, bone

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phosphatase IT-ALPll

disease, or hyperparathyroidism.

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Reference value: 4.5-13.0 King-Armstrong

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Nonspecific tumor marker for liver or bone

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unitsldl

malignancy.

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Alkaline phosphatase isoenzymes (I-ALP)

Hepatic, biliary

Used to distinguish between liver and bone

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Reference value: liver isoenzymes 50-70%

pathology when total serum ALP is elevated.

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T here are ALP isoenzymes for both liver and bone.

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Alpha l -fetoprotein (AFP1)

Heparic, biliary

A rumor marker for hepatocellular carcinoma in

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Reference value: <10 nglml

nonpregnant adults.

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AFP normally exists during pregnancy;

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otherwise. levels are very low.

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Ammonia (NHJ)

Hepatic

To evaluate or monitor liver failure,

Reference value: 15-45 �g1dl

hepatoencephalopathy, and the effects of

impaired ponal vein circulation.

Ammonia is a by-product of protein metabolism

and is converted ro urea in the liver.

Amylase, serum

Pancreatic

Assists in the diagnosis of acute pancreatitis and

Reference value: 27-131 U/liter

traumatic injury to the pancreas or as surgical

complication of the pancreas.

Amylase, urine

Pancreatic

Helps to confirm diagnosis of acute pancreatitis

Reference values:

when serum amylase levels are normal or

2-19 Ulh, (l-h, ,est)

borderline elevated.

4-37 Ul2 hrs (2·h, ,est)

170-2,000 U/24 hrs (24-h, ,csr)

Aspartate aminotransferase (AST, glutamate

Hepatic

Primarily indicates inflammation, injury, or

oxaloacerate transaminase [GOTI,

necrosis of the liver.

SGOT, transaminase)

AST is highly concentrated in the liver, but it is

Reference value: 8-20 U/litcr

also minimally present in skeletal muscle,

kidney, brain. pancreas, spleen. and lungs.

Bilirubin

Hepatic, biliary

Used to evaluate liver function, diagnose

Reference values:

jaundice, and monitor progression of

Total, 0.3-1.2 mg/dl

jaundice.

Direc, (conjuga,ed), 0-0.2 mg/dl

Total bilirubin is the sum of direct and indirect

Indirect (unconjugated), <1.1 mg/dJ

bilirubin.

Elevation in direct (conjugated) bilirubin

indicates hepatic jaundice, whereas elevation

52

in indirect (unconjugated) bilirubin indicates

prehepatic jaundice.

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Carbohydrate antigen 19·9 (CA 19·9)

Hepatic, pancreatic

A tumor marker used in the preoperative stag

Reference value: <37 U/ml

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ing of pancreatic cancer.

Hepatic cirrhosis can falsely elevate this value in

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>the absence of pancreatic cancer.

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Table 8-7. Continued

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Test

Involved Systems

Pu.rpose

Ceruloplasmin

Hepatic

Used to evaluate chronic active hepatitis, cirrho

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Reference value: 18-45 mgldl

sis, and other liver diseases.

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Fecal fat (fecal lipids, quantitative fat, 72-hr

Hepatic, biliary

The definitive test to identify steatorrhea (high

stool collection, quantitative stool fat)

levels of fat in the feces). This can be caused

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Reference value: <7 g/24 hrs

by hepatobiliary, pancreatic, and smaU

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intestine disease.

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Gamma-gluramyltransferase (y-glutamyl

Hepatic, bitiary, pancreatic

Used to detect hepatobiliary disease.

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transferase fGT], y-glutarnyl·

Levels will rise with posthepatic jaundice and

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transpepcidase I GGT, GGTP, GTPIl

orher diseases of the liver and pancreas.

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Reference values:

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Male, 22.1 Ullirer

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Female, 15.4 Ulliter

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Hepatitis virus tests

Hepatic

Distinguishes between the six rypes of vital

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Reference value: negative (no presence of

hepatitis (HAV, HBV, HeV, HOV, HEV,

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antibodies)

HGV).

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Presence of distinct antibodies for a specific

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virus will help confirm the diagnosis and

assist with treatment planning.

Lacrare dehydrogenase (LDH)

Hepatic

Can assist in the diagnosis of hepatitis, cirrhosis,

Reference value: 200-400 Ullirer

congestion of the liver, and hepatic anoxia.

However, this is a cosrly test to perform and

not a routine ponion of liver function tests.

Leucine aminopeptidase (LAP)

Hepatic, biliary, pancreatic

Used to detect heparobiliary disease and biliary

Reference value: 55.2 U/lirer

obstruction and to assist in differentiating

between hepatobiliary and bone diseases.

Lipase

Biliary, pancreatic

Used to diagnose pancreatitis and pancreatic

Reference value: <200 Ulliter

disease.

Lipase is a digestive enzyme used to digest fatry

acids.

5'-Nucleotidase (S'N, S'-t,rr)

Hepatic, biliary, pancreatic

Elevated levels help to identify extrahepatic or

Reference value: 2-17 rU/liter

intrahepatic biliary obstruction and cancer of

the liver.

Protein electrophoresis

Hepatic

Separates plasma proteins (albumin and

Reference value: albumin, 3.S-S.0 gldl

globulins) from the plasma to detect the

specific amounts of each protein type.

Decreased plasma protein levels are indicative of

hepatobiliary disease.

Serum proteins (albumin)

Hepatic

Provides general information about the

Reference value: 3.S-S.0 gldl

nutritional status, the oncotic pressure of the

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blood, and the losses of protein associated

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with liver, renal, skin, or intestinal diseases.

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Prothrombin time (PT, protime)

Hepatic

Elevated values are indicative of liver disease, as

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Reference value: 10-13 sees

the liver synthesizes clotting factors II, VII, IX

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and X.

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Sweat test (sweat chloride, cystic fibrosis

Pancreatic

Used to diagnose cystic fibrosis in children, as

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sweat test, iontophoresis sweat test)

these children have higher contents of sodium

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Reference value: 5-40 mEq/liter

and chloride in their sweat.

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Table 8-7. Continued

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Test

Involved Systems

Purpose

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Trypsinogen, immunoreactive assay (IRT,

Pancreatic

Screening test for cystic fibrosis in newborns of

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immunoreactive trypsin assay)

less than 1 mo of age.

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Reference value: <80 )Jg/liter

Elevated levels may indicate ptesence of disease,

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but the test has a high false-positive ratc;

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therefore, universal screening with this test is

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nOt mandated nationally.

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Urobilinogen, fecal

Hepatic, biliary

Used to confirm the diagnosis of !.iver discase or

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Reference value, 40-280 mg/day

biliary tract obstruction as well as identifying

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disorders of erythrocytes.

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Urobilinogen, urine

Hepatic, biliary

Used to screen for evidence of hemolytic anemia

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Reference value: